Plasmodium berghei was inoculated into various primates and the following species became infected: splenectomized Macaca arctoides (Asian); intact Cebus albifrons, C. apella, and Aotus trivirgatus (American); and splenectomized Erythrocebus patas, Cercopithecus pygerythrus, Cercocebus galentus, and Papio papio (African). The infections were all light and most of them were transient, but those in M. arctoides, C. galeritus, and P. papio lasted up to 78 days. Two chimpanzees (Pan troglodytes), one of them splenectomized, resisted infection. Babesia rodhaini also was inoculated into many of the above animals. Infections were produced in intact Cebus apella and in splenectomized Cercopithecus pygerythrus, Papio papio, and Pan troglodytes. The infections were subpatent and were demonstrated only by subinoculation into mice. Apparently these two parasites are less restricted in their range of possible hosts than was previously believed.
Present address: Clinical Research Centre, Harrow, Middlesex HAl 3UJ, England.